An amorphous MoS(x) modified g-C(3)N(4) composite for efficient photocatalytic hydrogen evolution under visible light

In this work, an MoS(x)/g-C(3)N(4) composite photocatalyst was successfully fabricated by a sonochemical approach, where amorphous MoS(x) was synthesized using a hydrothermal method with Na(2)MoO(4)·H(2)O, H(4)SiO(4)(W(3)O(9))(4) and CH(3)CSNH(2) as precursors, and g-C(3)N(4) nanosheets were produced using a two-step thermal polycondensation method. The hydrogen-evolution performance of the MoS(x)/g-C(3)N(4) composite was tested under visible light. The results show that the H(2)-evolution rate of the MoS(x)/g-C(3)N(4) (7 wt%) photocatalyst reaches a maximum value of 1586 μmol g(−1) h(−1), which is about 70 times that of pure g-C(3)N(4) nanosheets. The main reason is that amorphous MoS(x) forms intimate heterojunctions with g-C(3)N(4) nanosheets, and the introduction of MoS(x) into g-C(3)N(4) nanosheets not only enhances the ability to convert H(+) into H(2), but also promotes the separation of photoinduced electron–hole pairs for the photocatalyst. BET analysis shows that the specific surface area and pore volume of g-C(3)N(4) are decreased in the presence of MoS(x). XPS analysis manifests that MoS(x) provides a number of active sites. Mott–Schottky plots show that the conduction band of MoS(x) (−0.18 V vs. E(Ag/AgCl), pH = 7) is more negative than that of g-C(3)N(4) nanosheets.